Wire Harness Exterior Joining Structure for Thin Strong Resin Bonds
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Solution Overview
Problem
Existing methods for joining resin parts with different physical properties result in insufficient joining strength and require large joining portions, often necessitating complex processing or the use of adhesives.
Innovation Solution
A joining structure where a first member with a lower foaming ratio is combined with a second member having a higher foaming ratio, featuring a recessed joining portion formed by pressing and hot-melting the second member to extend into the first member, enhancing the joining strength while minimizing the joining portion's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a boss and hole mating mechanism is used to join resin members, then the joining structure is simple, but the joining portion becomes large in size and the joining strength is insufficient
Solution Approach 1:
The invention changes the physical state of the second resin from solid to molten by applying heat and pressure, enabling it to flow into the first member and form a recessed joining portion. This parameter change (solid→molten) allows the joining material to penetrate and bond with the first member, significantly improving joining strength while maintaining a compact structure.
Solution Approach 2:
The invention utilizes the phase transition of the second resin from solid to molten state during the joining process. By heating and pressing the second resin, it melts and flows into the first member, then solidifies to form a strong recessed joining portion. This phase transition enables effective bonding between members with different physical properties.
2Ease of manufacture
If adhesives or double-sided tapes are used to join members with different physical properties, then the joining process is simple, but the joining strength remains insufficient
Solution Approach 1:
The second resin acts as an intermediary material between the first member and the external environment. By melting and pressing the second resin, it forms a recessed joining portion that penetrates into the first member, creating a strong mechanical and chemical bond. This intermediary approach eliminates the need for separate adhesives while achieving superior joining strength.
3Strength
If a recessed joining portion is formed by pressing and hot-melting the second member, then the joining strength increases and the joining portion becomes thinner, but the processing complexity increases
Solution Approach 1:
The invention applies controlled changes in temperature and pressure parameters to melt and press the second resin, forming a recessed joining portion that extends into the first member. This parameter control enables the formation of a thin, strong joining interface without requiring complex multi-step processing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach achieves a stronger, thinner joining interface between members with different physical properties, eliminating the need for complex structures or adhesives, and significantly improving the joining strength.
Implementation Method 1
joining the first member and the second member to each other by forming a recessed joining portion, the recessed joining portion being formed by pressing and hot-melting the second member such that a resultant molten portion extends from an outer surface of the second member and reaches at least an interior of the first member
Data Source
AI summary
Provided are a joining structure, a joining method, an exterior body for a wire harness, and a wire harness capable of firmly joining members having different physical properties while reducing the thickness of a joint part. The joining structure 10 joins a first member 1 made of a first resin and a second member 2 made of a second resin, wherein: the second resin has physical properties having a higher foaming ratio than the first resin; and a recessed joint part 3 is provided which reaches at least the inside of the first member 1 from the outer surface side of the second member in a state in which the first member 1 and the second member 2 are superimposed. Furthermore, a method for manufacturing the joining structure 10 comprises the steps of: superimposing a first member 1 made of a first resin and a second member 2 made of a second resin having physical properties having a higher foaming ratio than the first resin; and joining the first member 1 and the second member 2 by forming the recessed joint part 3 by pressing and hot-melting the second member 2 until the recessed joint part 3 reaches at least the inside of the first member 1 from the outer surface side of the second member 2.